High pressure valves have been used in analytical processes and chromatographic processes in particular. There has been interest in applying higher pressures to obtain faster separations and increase through put. However, at ultra high pressures valves and other components become less reliable.
As used herein, the term “chromatographic processes” refers to processes that separate one compound from another compound as a result of difference in the affinity of the compounds to a stationary phase as the compounds travel in or around such phase.
The term high pressure chromatography refers to chromatographic processes which use pressures up to and including four thousand pounds per square inch. Ultra high pressure chromatography refers to chromatography processes which use pressures of greater than four thousand pounds per square inch.
As pumps and detectors used in analytical processes are operated at higher pressures, components of such equipment exhibit higher rates of failure. The loads on seals, bearing elements, springs and motors is greater. The torque required to turn shafts and axles is greater. As loads increase, alignment and positioning of flow control and sealing features becomes more critical to valve performance and useful lifetime.
It is desirable to have valves that can operate precisely and reliably at very high pressure for chromatography. It is desirable to have a valve that can be serviced to replace parts and components which experience wear and deterioration and retain other elements which remain fully functional.